1. Field of the Invention
The present invention relates to an evaporator having two heat exchanging parts juxtaposed in the flowing direction of wind passing through the evaporator.
2. Description of the Related Art
An evaporator having two heat exchanging parts juxtaposed in the flowing direction of wind is disclosed in Japanese Patent Application Laid-open Nos. 6-74679, 10-238896 and 2000-105091.
The inventor is developing an evaporator shown in FIG. 1. The evaporator 100 includes two heat exchanging parts juxtaposed on upwind and downwind sides in the flowing direction of wind, respectively.
The “downwind-side” heat exchanging part 110 has an upper tank 111, a lower tank 112 and a plurality of heat exchanging passages between the tanks 111 and 112. These heat exchanging passages are also communicated with the tanks 111, 112. Similarly, the “upwind-side” heat exchanging part 120 has an upper tank 121, a lower tank 122 and a plurality of heat exchanging passages between the tanks 121 and 122. As well, these heat exchanging passages are communicated with the tanks 121, 122.
The “downwind-side” heat exchanging part 110 and the “upwind-side” heat exchanging part 120 are arranged so as to overlap each other back and forth in the flowing direction of wind.
In the downwind-side heat exchanging part 110, the upper tank 111 is provided, on its right side, with an evaporator inlet 107. The upper tank 111 is partitioned to a first upper tank part 111a and a second upper tank part 11b by a partition 114, while the lower tank 112 is partitioned to a first lower tank part 112a and a second lower tank part 112b by a partition 115. The laminated heat exchanging passages are divided into a first path 110a, a second path 110b and a third path 110c in order from the right. Consequently, coolant introduced into the downwind-side heat exchanging part 110 via the evaporator inlet 107 flows through the first upper tank part 111a, the first path 110a, the first lower tank part 112a, the second path 110b, the second upper tank part 111b, the third path 110c and the second lower tank part 112b, in this order. Then, the coolant is introduced from the most downstream side (i.e. the second lower tank part 112b) of the downwind-side heat exchanging part 110 into the most upstream side (i.e. the first lower tank part 122a) of the upwind-side heat exchanging part 120 through a communication passage 109.
In the upwind-side heat exchanging part 120, the lower tank 122 is partitioned to a first lower tank part 122a and a second lower tank part 122b by a partition 124, while the upper tank 121 is partitioned to a first upper tank part 121a and a second upper tank part 121b by a partition 125. The upper tank 121 is provided, on its right side, with an evaporator outlet 108. Thus, the laminated heat exchanging passages are divided into a first path 120a, a second path 120b and a third path 120c in order from the right. Consequently, the coolant introduced into the upwind-side heat exchanging part 120 via the communication passage 109 flows through the first lower tank part 122a, the first path 120a, the first upper tank part 121a, the second path 120b, the second lower tank part 122b, the third path 120c and the second upper tank part 121b, in this order. Then, the coolant is discharged from the evaporator 100 through the evaporator outlet 108 on the right side of the second upper tank part 121b as the most downstream part of the upwind-side heat exchanging part 120.
Here noted, the paths overlapping on the upwind and downwind sides, for example, the first path 110a of the downwind-side heat exchanging part 110 and the third path 120c of the upwind-side heat exchanging part 120 have the number of heat exchanging passages equal to each other and the flowing direction of coolant opposite to each other, including the flowing of coolant in the tank parts.
With the above-mentioned structure, the liquid-phase coolant L in the heat exchanging parts 110, 120 is distributed as shown in FIG. 2A. Consequently, the distribution of liquid-phase coolant L in the whole evaporator is shown in FIG. 2B. In FIG. 2B, since the wind cannot be cooled down sufficiently in areas where the liquid-phase coolant L does not flow, in other words, only gas-phase coolant G does flow, the “blowout” temperature of the coolant is elevated disadvantageously.